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First Record of the Ozone Layer
The British Antarctic Survey's first documentation of the Antarctic ozone hole in 1985 and subsequent NSF-funded study of the phenomenon alerted the world to the danger of chlorofluorocarbons, or CFCs. -
The Ozone
Ninety percent of the ozone in the atmosphere sits in the stratosphere, the layer of atmosphere between about 10 and 50 kilometers altitude. -
Total Mass
The total mass of ozone in the atmosphere is about 3 billion metric tons. -
Chlorofluoraocarbons
Increased levels of human-produced gases such as CFCs (chlorofluorocarbons) have led to increased rates of ozone destruction, upsetting the natural balance of ozone and leading to reduced stratospheric ozone levels. These reduced ozone levels have increased the amount of harmful ultraviolet radiation reaching the Earth’s surface. When scientists talk about the ozone hole, they are talking about the destruction of stratospheric, “good,” ozone -
1970
Dramatic loss of ozone in the lower stratosphere over Antarctica was first noticed in the 1970s by a research group from the British Antarctic Survey (BAS) who were monitoring the atmosphere above Antarctica from a research station much like the picture to the right. -
Ozone
Ozone (O3 : 3 oxygen atoms) occurs naturally in the atmosphere. -
Ozone
Ozone forms a layer in the stratosphere, thinnest in the tropics (around the equator) and denser towards the poles. -
Ozone
It's ironic that at ground level, ozone is a health hazard - it is a major constituent of photochemical smog. However, in the stratosphere we could not survive without it. -
Antarctica
The long, cold, dark Antarctic winters allow the formation of polar stratospheric clouds, the particles of which form an ideal surface for ozone destruction. The returning sunlight provides energy to start the complex chemical reaction that results in ozone destruction. The ozone hole above Antarctica typically lasts about four months, from mid-August to late November.